There are many different types of sensors on the market, with each having specific capabilities, uses, and shortcomings. One particular type of sensor that utilizes light to detect objects is known as a proximity sensor.
Proximity sensors typically consist of a light source and a corresponding photodetector. The photodetector of a proximity sensor includes a number of photosensitive pixels. Proximity sensing (e.g., detecting a presence or proximity of an object near the sensor) involves transmitting light via the light source and then receiving light that reflects off an object-to-be-detected at the photodetector. The types of applications in which proximity sensors are used include mobile communication devices, industrial equipment, manufacturing equipment, etc.
Many proximity sensors are now being deployed in personal computing devices such as smartphones, laptops, Personal Digital Assistants (PDAs), tablets, etc. In particular, certain functions of the personal computing devices rely on a determination of whether or not an object is detected within a predetermined distance (e.g., within proximity) of the personal computing device. As with most components for personal computing devices, there is a general desire to miniaturize. More specific to proximity sensors, if a smaller proximity sensor can be achieved and the distance between the light source and photodetector can be reduced, then so too can the size of the opening in the computing device. It is, indeed, desirable to reduce the size of openings and holes in a computing device.